Nebula Invasion

Nebula Invasion is a 2D spaceship shooter with 3D effects. You fight alien attackers that march, dive-bomb and launch missiles, using a ship that can collect power-ups to increase its firepower. The game grows harder with each level, and the aliens and bosses attack more quickly as you progress.

Fight the invaders

Shoot aliens and boss missiles to release power-ups, which descend to your ship at random. The four power-ups are Double Cannon, Triple Cannon, Rapid Fire and Plasma Cannon with Shield. The shield protects you from missiles, bombs and fireballs. As you destroy enemies, the remaining invaders move faster, so you need to stay alert and avoid their attacks.

You face three kinds of aliens and their corresponding bosses. The first boss appears after you clear three levels and fires homing missiles at irregular intervals; shooting those missiles can yield power-ups. The second boss launches homing missiles and homing fireballs, though only its missiles can provide power-ups. The third uses fireballs alone, so the description recommends entering that fight with Rapid Fire or the Plasma Cannon. Boss pieces are worth 5 points, and defeating a boss can award a prize of 750, 950 or 1,250 points.

Ships and score

A large spaceship flies overhead and is worth 300 points when destroyed. After level 5, it fights back by dropping ticking time bombs. A smaller ship later appears and fires tiny homing fireballs; destroying it earns 1,000 points. You receive an extra life for every 10,000 points.

If the timer reaches zero, all invaders are destroyed and a new level begins. This prevents you from waiting for the ships to appear just to accumulate points.

Nebulas and progression

You begin in the Blue Nebula. After defeating its three bosses, you move to the Rust Belt Nebula; defeating that area's three bosses takes you to the Dog Spirit Galaxy. Deep Space and the Outer Limits follow. The appearance of space changes from level to level, and the nebulas grow brighter until you reach a new one.